Arc-lamp globe.



J. T. BEEGHLYN.

ARC LAMP GLOBE.

AYPLIOATION FILED AUG. 13, 1910 1,034.955. Patented Aug. 6, 1912.

2 SHEETS-SHEET 1.

Wjtn eases; Inventor:

John T. Beechlgn,

J. T. BEEGHLYN. ARC LAMP GLOBE. APPLICATION FILED 116.13, 1910.

1,034,955. Patented Aug. 6,1912.

2 SHEETSSHEBT 2.

Inventor John TBeec hl n, by is orne;;.

Witnesses UNITED. s'rarns PATENT orricn.

JOHN T. BEEGHLYN, ()F LYNN, MIASSACHUSE'IE'I. S,- ASSIGNOB ELECTRIC comm. A CORPQRATION. OF NEW YORK.

Ana-LAMP cLoBn'.

Application filed August 18, 1910. ser a No. 5730 34.

To all whmn it may concern: Be it known that I, JoHNT. BnacnLYN, a subject of the King of Denmark, residing at Lynn, county of Essex, State of'Massachusetts, have invented certain new and useful Improvements in Arc-Lamp Globes, of which the following is a specification.

My invention relates to. inclosing globes for electric arc lamps.

In the ordinary are lamp the inner surface of the arc-inclosing globe is a simple surface of revolution about a vertical axis which passes through the are maintained between the electrodes. The light rays proceeding from the .are or from the crater of the positive electrode, or from both, impinge upon the globe and partly pass through the same at the points of incidence and are partly reflected. These reflected rays, if they were not intercepted by the elec trodes, would again strike the inner globe surfaceand wouldthere again partly pass through and partly be reflected; and this process would be repeated theoretically ad infinz'tum, so that eventually all the light emitted at the arc would pass through the globe. But in most are lamps the electrodesare in vertical alinement coincident with the axis of revolution of'the globe surface, or there is at least one electrode, the lower one, located coincident with that axis, and the rays proceeding from the are are in the-ordinary globes reflected mostly downwardly and always inwardly toward the axis of revolution of the globe surface; they are therefore in great measure intercepted by the lower electrode and are thus lost.

It is the object of my invention to increase the efiiciency of arc lamps by so forming the arc-inclosing globe that most of the reflected light will be directed laterally past the electrodes.

The invention is illustrated in the accompanying drawings, in which- Figure 1 is a front-elevation of the globe; Fig. 2 is a vertical section of the globe showing the electrodes in elevation; Fig. 3 is a cross-section of the globe; and Fig. 4 is a.

dross-section of the globe with a diagram illustrating the reflection of light from the inner surface of the globe.

The profile of the globe here shown somewhat approaches the form of an ellipse, but

this is not essential, since almost any other general. outline willserve thepurposeof my invention. 1

The globe 1, instead .of'lieing formed as a surfaceof, revolutionabout a single vertical axis, is formed of anumber of contiguous. surfaces-2, 3, 4;- 13, each representing a .segmenflof, a surface of 'rev olution about gitS own and generally, but not necessarily, different, vertical axis, that does not pass through the are but is parallel to the axis of the lower vertical electrode '14. Consequently, any ray of. light proceeding from the arc thatstrikesany one of these sur faces, will bereflected in a plane defined by the incident, ray and the radius of curvature of the particular surface, drawn to the point of incidence from a point in itsiajxis of revo- .lution, that is to say,.the ,ray' will be refiected laterally past the vertical electrode, and will not'be intercepted bythe same. iThis will more fully appear farther-on.

A part of a lamp structure'only'is indi- Eeated in the drawing, because my invention electrode 14, is in a holderlfi, supportedby -a rod 16, which passes through a guide. or :bushing 17 inthe globe cover 18. The upper electrode is here shown, by. way of .Qi mple, as composed of two converging rods 19, and I the are 20, is established between the elec "trodes in any ordinary or improved manner, by any suitable mechanism, which is not here shown, because unnecessary for an understanding of the invention.

In Fig.4, the principle of construction of the are globe as well as ithe reflections from the same 'isdiagrammatically indicated. A

same as in Fig. 3, but upon a larger scale, and we may assume that the cross-section is through the middle of the globe. In the cross-section here shown, by way of exam ple, the length ofthe radius of curve ture of each of the segments 2, 3, 4,-etc., is thesame; thus, theradius of curvature of segment 2, is represented by the lines 2 2f; the radiusofcurvature of segment 3, is represented by 3 3"; the radius of curvathe radius of curvature ofs egment'fi, is representedby 555"; the radius of curve;-

ithe adius of'- curvature of segment I, IS

Patented Aug. e, 1912.

3 is not dependentupon any particular struc ture of the 'mechanism. The lowenvertiealtureof, segment 4, isrepresented; by 4" t",

cross-section of the globe is here showmthe ture of segment 6,is represented by 6 6 of the segmental surfaces of revolution 2 and 7, i. e.,-it represents the horizontal projection of the axis of revolution of the segmental surfaces 2 and -7.- Similarly, the point 3 is the horizontal projection ofthe axis of revolution of the segmental surfaces 3 and 10, and so forth,and the line which connects all these points 2 ,3", 4", etc., is the horizontal projection of a surface that is the geometrical locus of all the axes of revolution of all the surfaces of which the globe is composed. In the example here shown, in which the segments are arranged symmetricallv around a common axis, the

line 2* 3" t 5" G" 8", is a circle, as indicated in dotted lines, which means that the locus of the axes of curvature ,of the segments, no matter how many segments theremay be, is a circular cylinder; but thisis-not essential, since the invention is not dependent upon a synnnetrical arrangement offthe'sgments. lVith a difi'erent arrangement of the segments, the locus of their a xeslof revolution might be an t-lliptical cylinder, 01'' a prism, or, in fact, may have any configuration, since it is by no means-necessary that the axes of revolution all parallel to the axis of the electrodes.

In Fig. 4, the inner circle 21 may repre sent the size and location of. the lower electrode, and the-center of this circle may represent the are 20 established between the electrodes, whichis here, for the sake of simplicity, considered as a int.

A ray of light proceeding from the arc and s riking any of the segmental surfaces of the globe, say the ray 205, will be reflected in the plane defined by that ray and by the radius of curvature 5" 5, drawn to the point of incidence, in the direction 5 :0, well past the vertical electrode, and generally downwardly, This my will, therefore, not be intercepted by the electrode and will not be lost. The same thing is true of any .other ray that proceeds from the arc and strikes the segment 5, 'as for instance the ray 20-5, which will be reflected in the plane defined by the ray itself and by the radius of curvature 5" 5, drawn to the point of incidence, in the-direction 5 y, well past the vertical electrode. It will now be clear, that the same is true of all rays that proceed from the arc and strike any of the segmental surfaces of the globe at any point between the edges where these segments meet. The rays, however, which, proceeding from the arc reach theglobe at the lines of junction of two contiguous segments, will generally be reflected toward the axis of the vertical electrode and will thus be lost; but these rays are only an infinitesimal portion of the rays emitted by the arc, and it may therefore be said that practically no light is los by interception by the electrodes.

In the specimen of globe hcre illustrated I have shown twelve segmental surfaces, all

ofthe same size and so grouped as to present to the arc concave surfaces, meeting'alternately at direct and reentering angles; but the invention is obviously not restricted to such arrangement, since the number of segments is arbitrary and the successive segments may have diti'erent'widths and may join each other at all sorts of angles; a symmetrical arrangement, such as shown, is however generally preferable.

It is evident that my invention is not confined to a globe which is entirely composed of segmental surfaces of revolution about axes that are eccentric to the axis of the lower electrode, or to the' main axis of the globe as a whole, since it is quite practicable to have aportion or portions of the inclosing globe made with 'a surface of revolution about an axis coincident with that of the vertical electrode. It is also clear that the axes of revolution of. the segments may be at infinite distances, which means that the segments would, in'cross-section, be represented by straight lines.

What I claim as new and desire to secure by Letters'Patent of the United States, is,-

1. In an electric arc-lamp having a lower vertical electrode, an arcinclosing globe of light-transmitting'material formed with refleeting surfaces of revolution about axes that are eccentric to the axis of the lower electrode, each radius of curvature of each surface'being in a vertical plane extending laterally past the lower electrode.

2. In an electric arc-la mp having a lower vertical electrode, an arc-inclosing globe of light-transmitting material, formed with a continuous series of contiguous segments of reflecting surfaces of revolution about axes that are eccentric to the vertical electrode, each radius of curvature of each surface beingin a vertical plane extending laterally past the lower electrode.

In witness whereof, I have hereunto set mv hand this eleventh day of August. 1910.

JOHN T. BEECHLYN.

\Vitncsscs FRANK G. HATTIE, Cnanmzs A. BARNARD.

Copies of this patent may be obtained (or five cents each, by addressing the Commissioner of Patents.

' Washington, D. C. 

